Oriented Growth of α-MnO2 Nanorods Using Natural Extracts from Grape Stems and Apple Peels

Abstract

We report on the synthesis of alpha manganese dioxide (α-MnO2) nanorods using natural extracts from Vitis vinifera grape stems and Malus domestica ‘Cortland’ apple peels. We used a two-step method to produce highly crystalline α-MnO2 nanorods: (1) reduction of KMnO4 in the presence of natural extracts to initiate the nucleation process; and (2) a thermal treatment to enable further solid-state growth of the nuclei. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) images provided direct evidence of the morphology of the nanorods and these images were used to propose nucleation and growth mechanisms. We found that the α-MnO2 nanorods synthesized using natural extracts exhibit structural and magnetic properties similar to those of nanoparticles synthesized via traditional chemical routes. Furthermore, Fourier transform infrared (FTIR) shows that the particle growth of the α-MnO2 nanorods appears to be controlled by the presence of natural capping agents during the thermal treatment. We also evaluated the catalytic activity of the nanorods in the degradation of aqueous solutions of indigo carmine dye, highlighting the potential use of these materials to clean dye-polluted water.

Nanostructured MnO2 as Electrode Materials for Energy Storage

“…Urchin-like α -MnO 2 materials were also prepared through a simple precipitation reaction of H 2 SO 4 and KMnO 4 in aqueous solution heated at 85 °C [90]. A two-step green precipitation route was used for the reduction of KMnO 4 in the presence of natural extracts such as extracts of grape stems and apple peels to initiate the nucleation process [91]. TEM images showed the presence of short and long nanorods with diameters in the range 28–70 nm and lengths in the range 85–180 nm, which form dense agglomerates.…”

Green Synthesis, Characterization and Application of Proanthocyanidins-Functionalized Gold Nanoparticles

“…In addition, the development of novel synthetic strategies for the preparation of monodisperse gold nanoparticles and the assembly of nanoparticles into one- and two-dimensional structures are critical for their applications [ 7 , 8 ]. Recently, there has been a renewed interest in green synthesis of nanoparticles [ 9 , 10 , 11 , 12 , 13 , 14 ]. For example, gold nanomaterials were synthesized by using plant extracts as both the reducing and capping agents [ 15 ].…”

A review on the origin of nanofibers/nanorods structures and applications

“…The schematic representation for the formation of α-MnO 2 nanorods via the nucleation process is shown in Fig. 1 [3]. After forming the nuclei, the nuclear clusters are being heated at 600 and 800 o C temperatures.…”